Refrigerated shelf stable dough

ABSTRACT

A dough composition for making quality, thinly sheeted farinaceous food products such as pie crust or the like and which is shelf stable. The dough composition contains a high-starch, low-enzyme flour, shortening, water, gluten and preservatives. The composition is particularly adapted for making a pie dough which, during manufacture, is pre-sheeted and folded twice for packaging, and then is unfolded by the consumer for use.

This is a continuation of application Ser. No. 117,312 filed Jan. 31,1980, now abandoned.

FIELD OF THE INVENTION

The present invention relates to a pie crust and a pie crust formulationfrom which a folded pie crust or the like can be made.

BACKGROUND OF THE INVENTION

For centuries, people have made pie crust by hand, generally just priorto making a pie. The crust-making process is somewhat difficult,timeconsuming, messy, and very often is a source of frustration for thepie-maker. Pies were once a traditional food item, but because of theinconvenience and the lack of time that people have for making pies,pies have fallen somewhat into disfavor. In today's environment ofdesire to quickly prepare meals with food products of high quality,there has been a long-felt need for eliminating the crust-making portionof the pie-making procedure. Thus, it would be highly desirable toprovide a ready-to-use, high quality pie crust which would simplify themaking of pies by eliminating the pie crust making portion of the piemaking process.

Currently, prepared pie crusts are available in frozen form and arecompletely formed and in their own baking pans. However, the quality ofsuch crusts is not very good. Furthermore, they are extremely fragile,require a significant amount of storage space in the household freezer,and are not very convenient for making two-crust pies. Numerous attemptshave been made to provide a non-frozen pie crust either in sheeted formor in a ball or stick "add water and mix" form which would be rolled outinto the sheet form by the consumer. These pie crusts have to date metlimited consumer acceptance primarily because of lack of completeconvenience with the ball and stick mix forms and because of poorquality with the sheet form.

In the past, The Pillsbury Company provided an alternative to theabove-described ready-to-use pie crusts by having a refrigerated foldedpie crust which was in sheeted form and the only steps necessary for usewere unpackaging, unfolding, and placing the pie crust in the pie pan.However, this pie crust had some shortcomings, foremost among them,excessive browning during the baking of the product which had been heldfor an extended shelf life (e.g., 45 days or more). Other major problemsincluded off flavors and cracking upon unfolding the crust. However,market tests indicated that the concept of a folded pie crust would meetwith high consumer acceptance if the problems exhibited by the piecrusts could be overcome.

The present invention overcomes the problem of excessive baked browningof a pre-folded pie crust late in shelf life as well as eliminates orreduces the flavor problem and considerably reduces the cracking.Excessive browning of the baked product had not been a problem in thepie crust which was relatively freshly made, for example, less than 35days, but commercial distribution requires 75 to 90 days of refrigeratedshelf life. The described pie crust of this invention does not brownexcessively during baking throughout 90 days of refrigerated shelf lifeand has been shown to be of high quality throughout that shelf life.

By controlling the composition of the formulation as hereinafterdescribed, a pie crust of acceptable quality can be made which exhibitsgood flakiness, non-greasiness and good browning characteristics afterextended shelf life while substantially reducing cracking uponunfolding.

DETAILED DESCRIPTION OF THE INVENTION

The following disclosure will be directed to the making of a pie crust;however, it is to be understood that food products other than pie crustssuch as pizza crusts, puff pastry, tortillas, etc., can be producedsimilarly. The following formulation can be used to produce afarinaceous food product which is adapted for refrigerated storagehaving a shelf life of about 90 days. What is meant by refrigeratedstorage is that the product can be stored in an uncooked condition at atemperature of about 40° to 45° F. for a shelf life of up to 90 days andstill produce a high quality product which browns properly, tastes good,exhibits flakiness, and is resistant to cracking when unfolded.

The dough broadly includes a high-starch, low-enzyme flour, shortening,water, salt, gluten (optional), a preservative system and food coloring.

The flour composition is of major importance in reducing Maillardbrowning during baking, particularly after extended shelf life,particularly in the range of between about 35 days and about 100 days.

The desirable flour has a high starch level, low enzyme level andminimal starch damage. Because such a flour is difficult to obtain as astandard product, it has been found desirable to modify a standard flourby adding additional starch thereto to achieve a flour component havinga high starch level and a low enzyme level (hereinafter this will bereferred to as the flour blend). Any suitable starch can be added, suchas wheat flour starch, potato starch, corn starch, tapioca starch, etc.In modifying typical standard flours, it is preferred that the flourblend composition consist of between about 30% and about 70% by weightadded starch on a dry starch/dry flour basis and more preferably betweenabout 40% and about 60% and most preferably between about 45% and about55% added starch (typical standard flour contains about 84% to about 89%dry starch by weight of dry flour). Thus, the flour blend containsbetween about 92% and about 98% starch (dry starch basis), morepreferably between about 93% and about 97% starch and most preferablybetween about 94% and about 96% starch by weight of dry flour blend.Thus, the dry starch fraction of the dough is between about 37% andabout 47%, more preferably between about 39% and about 45% and mostpreferably between about 40% and about 44% by weight.

The flour blend is present in the dough in a range of between about 38%and about 50% by weight of the dough, with this range being based on dryflour blend weight, and preferably between about 40% and about 48%, andmore preferably between about 42% and about 46%.

Preferably, the flour blend contains less than about 0.2 absorptionunits of enzymes in the dry flour, more preferably less than about 0.1absorption units and most preferably less than about 0.5 absorptionunits as measured by spectrophotometry in the following test procedure.

One gram of flour was blended for 45 seconds in a Lourdes mixer with 50ml of 0.1 molar pH 6.5 phosphate (K) buffer. After centrifuging, 1 ml ofthe clear supernatant was pipetted into a 1 cm spectrophotometer cellalong with 1 ml of a 0.02 molar quaiacol solution. The temperature was25° C. 1 ml of 0.3% hydrogen peroxide solution was added rapidly,contents of the cell mixed, and timing commenced. Absorbance at 470 nmwas recorded after 1 minute and again after 2 minutes. Absorbance at 470nm after 2 minutes for 20 mg sample/ml was taken as the peroxidaseactivity of the sample.

The enzyme type which is of concern in the above-cited levels and testis peroxidase which is used as an indicator enzyme to indicate totalenzyme activity of the flour blend. Typical standard flours have enzymeactivity of 0.4 to 1.5 absorption units by this test procedure.

The reason for having a low enzyme level is that the enzymes affect therate of hydrolysis of starch into sugars and this affects the bakedbrowning (Maillard browning) at the end of shelf life. Maillard browningis a result of chemical reactions that require reducing sugars and aminoacids as reactants and the amount of browning is dependent on theconcentrations of the reactants present. Thus, if too much hydrolysisoccurs, then the reducing sugars will accumulate and excessive Maillardbrowning after extended shelf life will occur as is evidenced by thefollowing table.

    ______________________________________                                        BROWNING AS A FUNCTION OF LEVEL                                               OF ENZYMES IN FLOUR                                                           Browning of Edge of Crust                                                                          Enzyme*   Time at 70° F.                          Experiment #                                                                           Variable    Level     (Days)                                         ______________________________________                                                                       2   4   8   9   14                             1        Control     1.0-1.5   4   6   6   7   5.5                                     Low Enzyme  .05-.1    3   5.5 5   3.5 5.5                                                           1   4   7   10                                 2        Control     1.0-1.5   7.3 8   6.5 7.5                                         Low Enzyme  .05-.1    5   6   5   6                                                                 0   5   10  14  17                             3        Medium Level                                                                              .3-.8     6   7   7   8   10                                      Low Enzyme  .03-.05   6   6   6   6   6                              Key for browning:                                                             Scale of 0-10                                                                  0 = White, No Browning                                                       10 = Charred, Extremely High Browning                                         ______________________________________                                         *Flour blend enzyme level as measured by the indicator enzyme peroxidase,     in absorption units, as described on page 6.                             

Excessive Maillard browning can also be caused by excessive physicaldamage to the starch granule, which makes the starch molecules moresusceptible to hydrolysis and again leads to an accumulation of reducingsugars. Therefore, it is preferred to have a flour blend with starchdamage of less than 10%, more preferably less than about 5% and mostpreferably less than about 3% by weight as measured by the AACC method76-30A. By keeping the starch quantities above minimal levels and starchdamage below maximum levels and a low amount of enzymes in the flourblend, excessive browning can be prevented through 90 days ofrefrigerated shelf life as is evidenced by Tables II and III below:

                  TABLE 2                                                         ______________________________________                                        SHELF-LIFE BROWNING AS A                                                      FUNCTION OF STARCH                                                            Browning of Edge of Crust                                                     ______________________________________                                               Time at 40° F. (Weeks)                                                   1      3      6    9                                                 ______________________________________                                         0% Starch*                                                                            5      6      6    6                                                 50% Starch                                                                             2      3      5    4                                                        Time at 40° F. (Weeks)                                                               Time at 70° F. (Days)                                      1         3         4    9    11   16                                ______________________________________                                         0% Starch                                                                             6         6         7    7    8    9                                 33% Starch                                                                             6         5         5    6    6    7                                 67% Starch                                                                             4         3.4       3.5  3    4    4                                        Time at 40° F. (Weeks)                                                   4       61/2    91/2                                                 ______________________________________                                         0% Starch                                                                             9.8     9.5     9.2                                                  50% Starch                                                                             7       8       8.2                                                         Time at 40° F. (Weeks)                                                   0       6       9                                                    ______________________________________                                        15% Starch                                                                             5       8.7     9                                                    30% Starch                                                                             5       8.5     8.5                                                  45% Starch                                                                             4.3     7.7     7.7                                                  Key for browning:                                                             Scale of 0-10                                                                  0 = White, No Browning                                                       10 = Charred, Extremely High Browning                                         ______________________________________                                         *Percentage of starch given as added dry starch per dry flour blend on a      weight basis.                                                            

                  TABLE 3                                                         ______________________________________                                        SHELF-LIFE BROWNING AS A                                                      FUNCTION OF STARCH                                                            Browning of Center of Crust                                                   ______________________________________                                               Time at 40° F. (Weeks)                                                   1      3      6    9                                                 ______________________________________                                         0% Starch                                                                             5      6      6    6                                                 50% Starch*                                                                            2      3      4    3                                                        Time at 40° F. (Weeks)                                                               Time at 70° F. (Days)                                      1         3         11      16                                       ______________________________________                                         0% Starch                                                                             4         6         7       7                                        33% Starch                                                                             4         4.5       5       5                                        67% Starch                                                                             1         3.5       2       1                                               Time at 40° F. (Weeks)                                                   4       61/2    91/2                                                 ______________________________________                                         0% Starch                                                                             8       8       8.8                                                  50% Starch                                                                             4.2     6       7.2                                                         Time at 40° F. (Weeks)                                                   0       6       9                                                    ______________________________________                                        15% Starch                                                                             3.7     7.3     7.3                                                  30% Starch                                                                             3.5     6.5     6.0                                                  45% Starch                                                                             2.8     6.0     6.0                                                  Key for browning:                                                             Scale of 0-10                                                                  0 = White, No Browning                                                       10 = Charred, Extremely High Browning                                          *Percentage of starch given as added dry starch per dry flour blend on a      weight basis.                                                            

It has also been found that by having high levels of starch and lowlevels of protein in the dough that flakiness can be improved asillustrated in Table IV.

                  TABLE IV                                                        ______________________________________                                        Visual Flakiness as a Function                                                of Starch, Shelf-life                                                                    Time at 70° F. (Days)                                       ______________________________________                                                     4     9          11  16                                           0% starch*  4     2          1   1                                           33% starch   5     7          6   5                                           67% starch   7     7          7   10                                                       4     61/2       91/2                                             0% starch   2     2          5                                               50% starch   7     8.5        8                                               Scale: 0-10                                                                    0 = non-flaky appearance                                                     10 = extremely flaky appearance                                               ______________________________________                                         *Percentage starch given as added dry starch by dry flour blend on a          weight basis.                                                            

Too high levels of starch will result in a dough of such low proteinlevels that the dough will be weak and fragile. Such a fragile doughwill not process well and will crack excessively upon unfolding thecrust before baking. What is meant by excessive cracking is theexistence of one or more cracks greater than 1 inch in length. This isbecause the protein network is needed to hold the starch and doughtogether and when the protein level is reduced, the network is weakenedresulting in a fragile dough.

The protein level that is used to provide an adequate network to preventexcessive cracking depends on the way the dough is handled during theprocess. For example, if the dough is hand folded, the process is moregentle and requires less protein than if the crusts are machine folded.In the case of hand folding, a minimum of about 3% protein by weight ofdry flour blend is required. In this case, the range of protein by dryflour blend weight base is about 3% to about 12%, preferably about 3.5%to about 10% and more preferably about 4% to about 8%. In the case ofmachine folding, a higher level of protein may be required and this maybe accomplished by blending with the flour additional wheat gluten inthe range generally between about 2% and about 4% by weight based on dryflour blend weight. The total amount of protein in the flour blend inthe machine folded case should be a minimum of about 4.5% by weight ofdry flour blend. In this case the range of protein should be about 4.5%to about 12%, preferably about 5.5% to about 10% and more preferablyabout 6% to about 8%.

In the dough, in the case of hand folding, protein should be present ona weight basis in the range of between about 1.5% to about 6%,preferably 1.7% to about 5% and most preferably in the range of betweenabout 2% and about 4%. In the case of machine folding, it is preferredthat protein be present in the dough in the range of between about 2.2%and about 6% by weight, preferably between about 2.7% and about 5% andmost preferably between about 3% and about 4% by weight.

Dry standard flour is in the dough, preferably in a range of betweenabout 17% and about 27% by weight, more preferably between about 19% andabout 25% and most preferably between about 21% and about 23%. Theseranges, however, may change depending upon the type of flour used.

Shortening is necessary at relatively high levels to give the desiredtexture of baked pie crust. The preferred shortening level is in therange of between about 24% and about 35% of the total weight of thedough, more preferably between about 26% and about 34% and mostpreferably between about 28% and 32%. If the shortening level is toolow, the baked product will not have the desired tenderness; if thelevel is too high, the product will become difficult to process, maycrack excessively upon unfolding the pre-folded crust and the bakedproduct used in a two crust filled pie may acquire an oily texture.

The preferred shortening is prime steam lard, about 1% to about 10% ofwhich has been fully hydrogenated. It has a solid fat index (SFI) at 50°F. of about 29 to about 36, preferably about 30 to about 35 and morepreferably about 31 to about 33 as measured by the standard AOCSdilatometry method CD10-57. The shortening has a Wiley melting point ofat least about 108° F. as measured by test procedure 28.009 as found inthe 12th edition of Methods of Analysis by the AOAC. Preferably, theWiley melting point is between about 108° F. and about 118° F., morepreferably between about 110° F. and about 115° F. and most preferablybetween and including about 111° F. and about 113° F. A preferredshortening is lard or any other shortening having the following fattyacid composition: C₁₄, 0-3%; C_(14:1), 0-1%; C₁₆, 23-28%; C_(16:1),1-5%; C₁₈, 14-20%; C_(18:1), 41-46%; C_(18:2), 8-11% on a mole basis asdetermined by the Iverson method in Journal of AOAC 48, 3, p. 482(1968).

If the shortening has an SFI value exceeding about 36 and/or a Wileymelting point exceeding about 118° F., the product will be difficult toprocess without splitting the thin dough sheet during sheeting and theproduct will also crack excessively upon unfolding. If the shorteninghas an SFI value of less than about 29 and/or a Wiley melting point ofless than about 108° F., a baked product used in a two-crust filled piebecomes excessively greasy and oily.

Also, it is preferred that the shortening be deodorized and have freefatty acids of less than or equal to about 0.2% by weight of totalshortening (by the official method of the AOCS, CA 5A-40) and a peroxidevalue of less than or equal to about 3 milli-equivalents per kg of totalshortening (by AOCS official method CD 8-53). By having this level offree fatty acids and the proper level of peroxide value, rancidity canbe eliminated.

Water is present in the dough. The water is introduced into the doughgenerally by two means: the flour blend contains a certain amount ofwater, and water is normally added to the dough as a separateingredient. The total water in the dough is preferably in the range ofbetween about 19% and about 25% by weight of dough, more preferably inthe range of between about 20% and about 24% and most preferably betweenabout 21% and about 23%. Given typical moisture levels for flour blend,water will be added to the dough as a separate item in the range ofbetween about 14% and about 20% by weight of dough, more preferablybetween about 14.5% and about 18.5% and most preferably in the range ofbetween about 15% and about 17%.

In the preferred formulation, an antimycotic preservative system isadded to prevent molding. A preferred preservative system which has beenfound effective to prevent mold growth at 40° F. for about 90 days issodium propionate in the range of between about 0.05% and about 0.6% byweight of the dough and potassium sorbate in the range of between about0.05% and about 0.15% by weight of total composition and citric acid inan amount up to about 0.07% by weight of dough.

Salt is added to the composition at a level of about 1.2% to about 2% byweight of dough for flavor purposes and also to reduce water activity.The water activity should be between about 0.9 and about 0.94 asmeasured by the standard method of electric hygrometry.

The pH of the dough is also important in preventing molding by enhancingthe effectiveness of the preservative system. Preferably, the pH of thedough is between about 5.0 and about 5.6. Dough pH can be controlled bybleaching the flour and also by the addition of citric acid.

Food coloring can also be added to the dough in minor amounts. In apreferred form of the present invention, FD & C yellow #5 can be addedin an amount of up to about 0.001% by weight of dough and FD & C red #3can be added in an amount up to about 0.0001% by weight of the dough.

In the process of making dough, shortening, either in liquid form orsolid form, is added to the chilled flour. The ingredients are mixed todisperse the shortening and flour to form a blend. Either during orafter the shortening addition, water is added with additional mixing todisperse the water within the mixture and to hydrate and develop gluten.The other ingredients, such as salt, preservatives and color, are addedwith the water. In order to produce a long-flake crust, it is desirableto have small pellets of shortening 1/16 to 3/8 inch in diameter in thedough.

To produce small pellets of the correct size, it is desired that theflour blend be chilled before mixing with the shortening. When usingheated liquid shortening, preferably slightly above its melting point,it has been found that having the flour blend at a temperature betweenabout -40° F. and about -20° F. will achieve the formation of adequateshortening pellets. When using solid fat, it has been found that usingflour at a temperature of less than about 50° F. has been suitable.After the shortening and flour blend have started mixing, water isadded. The temperature of the flour, shortening and other componentsshould be such that after the dough has been mixed, it is at atemperature in the range of between about 50° F. and about 70° F., morepreferably in the range of between about 55° F. and about 65° F. andmost preferably is about 60° F.

It has been found that exposing the dough to vacuum above a certainlevel and for a certain time period, significant improvements in doughcharacteristics and product quality can be obtained. For example, thedough becomes significantly stronger and more extensible. Also, thebaked product is significantly flakier. The subjection or exposure ofthe dough to the vacuum process can occur at any time after the start ofthe mixing of the dough to achieve the heretofore describedimprovements.

The application of vacuum should be such that the dough is exposed to avacuum of at least about 27.5 inches of mercury, more preferably atleast about 28 inches of mercury and most preferably about 29 inches ofmercury. The required time of exposure depends upon the level of vacuum,whereby the higher the vacuum level, the lower the exposure time andconversely. The time of exposure is that time period which the vacuumlevel is at least equal to or exceeds the minimum prescribed vacuumlevel. Thus, the time of exposure to the minimum vacuum level shouldexceed at least about 0.5 seconds, more preferably at least about 1second and most preferably at least about 3 seconds. However, for alarge dough mass, four minutes or more exposure time may be required.

The dough should be allowed to expand during the application of thevacuum or the previously described characteristics will not occur. Theapplication of vacuum at the prescribed level expands the doughvolumetrically at least about 1.1 times the initial volume of the dough(i.e., a 10% increase in volume). If the dough is in sheet form of up toabout 1/4 inch thick, the dough may expand about 1.5 times the originalvolume (a 50% increase).

The expansion of the dough is dependent on the flexibility of the doughand, hence, is dependent on its temperature. The temperature of thedough during vacuum exposure should be at least about 55° F., morepreferably at least about 65° F. and most preferably about 75° F.

The change in the dough characteristics after subjection to vacuum canbe attributed to a modification of the dough structure. After the doughis mixed, it normally contains many relatively large gas or air cellsthat can be seen under a light microscope with a 10× magnification.After subjection of the dough to the vacuum process, the majority of theair cells disappear from the dough. The vacuum process expands the aircells and at the prescribed vacuum conditions, the air cells overcomethe tensile strength of the dough and are released. The increasedextensibility and strength of the dough is due to a more uniform doughstructure. One explanation for increased flakiness of the baked productmay also come from a reduced number of air cells in the dough. Forexample, if the air cells are found uniformly through the dough in greatnumbers, the dough expands uniformly during baking resulting in auniform, non-flaky appearance. With fewer air cells, the dough canexpand in discrete areas of the crust during baking, which results in aflakier appearance of the final baked product.

The dough can be used and further processed as desired. For making piecrusts or the like, the dough is sheeted with any suitable sheetingapparatus. During the sheeting operation, it is preferred that the doughbe at least about 55° F. to prevent disruption of the continuous sheet,and the temperature should not exceed about 75° F., as the material maybecome difficult to process.

After sheeting, the dough is cut and folded. Preferably, a separatingsheet is positioned on opposite sides of the pie crust. The pie crust isthen packaged in a heat sealable pouch or the like.

In final form the dough may be packaged in an atmosphere of fat and/orwater soluble gas. This aids in maintaining the highly flaky characterof the dough which has been vacuum processed.

The gas should have a solubility at 20° C. and atmosphere pressure of atleast about 0.1 volumes of gas per volume of water and/or at least 0.05volumes of gas per volume of shortening. Particularly suitable gases areCO₂ and N₂ O.

It is to be understood that while there has been illustrated anddescribed certain forms of the present invention, it is not to belimited to the specific form disclosed herein except to the extent thatsuch limitations are found in the appended claims.

What is claimed is:
 1. A method of processing dough to improve bakedflakiness, said method comprising:mixing flour, shortening and water andthereby form a dough mass, said shortening being in an amount sufficientto provide flakiness in a cooked product made from said dough mass;exposing said dough mass to a reduced pressure environment wherein thevacuum pressure is at least about 27.5 inches of mercury, said exposureis for a time of at least about 1/2 second with said time being thattime period for which the vacuum pressure is at least equal to thespecified vacuum pressure, during said exposing, said dough is allowedto volumetrically expand at least about 1.1 times its pre-exposurevolume; and releasing said vacuum prior to commencement of cooking.
 2. Amethod of processing dough to improve baked flakiness as set forth inclaim 1 wherein:said vacuum pressure is at least about 28 inches ofmercury.
 3. A method of processing dough to improve baked flakiness asset forth in claim 2 wherein:said vacuum pressure is at least about 29inches of mercury.
 4. A method of processing dough to improve bakedflakiness as set forth in claim 1, 2 or 3 wherein said volumetricexpansion is at least about 1.5 times the pre-exposure volume.
 5. Amethod of processing dough to improve baked flakiness as set forth inclaim 4 including storing the dough wherein the thus exposed doughduring storage is maintained in a gaseous environment substantiallycomprising CO₂.
 6. A method of processing dough to improve bakedflakiness as set forth in claim 4 including storing the dough whereinthe thus exposed dough during storage is maintained in a gaseousenvironment substantially comprising N₂ O.
 7. A method of processingdough to improve baked flakiness, said method comprising:mixing flour,shortening and water and thereby form a dough mass wherein said doughmass has shortening in an amount of at least about 24% by weight;exposing said dough mass to a reduced pressure environment wherein thevacuum pressure is at least about 27.5 inches of mercury, said exposureis for a time of at least about 1/2 second with said time being thattime period for which the vacuum pressure is at least equal to thespecified vacuum pressure, during said exposing, said dough is allowedto volumetrically expand at least about 1.1. times its pre-exposurevolume.
 8. A method of processing dough to improve baked flakiness asset forth in claim 7 wherein said vacuum pressure is at least about 28inches of mercury.
 9. A method of processing dough to improve bakedflakiness as set forth in claims 7 or 8 wherein said volumetricexpansion is at least about 1.5 times the pre-exposure volume.